This invention relates to a more efficient device to transfer heat from the fireplace to the room and utilization of the waste heat which normally goes up the chimmey flue. Several devices have been developed which tend to utilize the waste heat from the fireplace.
One such device consists of bent tubing in an arc supported together to form a cradle for the burning logs to sit on. The air passes through the tubes from the bottom and is projected into the room by natural convection or forced air. Problems develop with the excessively high temperature experienced at the tube outlet of this device which cause a low air flow rate under natural convection. Forced air convection fans are esthetically obtrusive in that they are not normally built into a fireplace and must sit out in open view. Further they can be easily damaged when feeding logs into the fireplace.
Other such devices utilize the installation of duct work into the brick work of the fireplace utilizing an air heat exchanger which passes through the flue to collect heat and out into the room. These devices cannot be added to existing fireplaces and require constant inspection to be sure that they maintain their seal to prevent carbon monoxide from leaking into the room through a leak within the heat exchanger.
Further, several devices in the past have utilized steam in a closed circulatory system requiring pumps, expansion valves, and large storage boilers be built into the fireplace and which cannot readily be added to existing fireplaces.